The PIN_PDN was not set as output, therefore it would not transition to
LOW for 150 ns and then stay HIGH to properly enable the CODEC. The
CODEC now powers up, at least.

The test puts a 440 Hz sinewave on one channel, and a 220 Hz on the
other

https://forum.pjrc.com/threads/31351-Teensyduino-1-26-Beta-3-Available?p=87620&viewfull=1#post87620

https://github.com/PaulStoffregen/Audio/pull/119

https://forum.pjrc.com/threads/27409-Play-RAW-from-Serial-Flash?p=77666#post77666

Change width to pulseWidth, update the example, keywords.txt and
gui/list.htm

pulse plus example